1. Field of the Invention
The present invention relates to an imaging device having a rotatable specific-effect optical element such as a polarizing filter that produces a specific photographic effect when positioned in an optical path of a photographing optical system and rotated in this optical path.
2. Description of the Related Art
In rotatable optical elements such as a polarizing filter and a cross filter, which give a specific photographic effect to an object image when operated to rotate, the photographer manually rotates the rotatable optical element to adjust the rotational position thereof while viewing the object image through a viewfinder or the object image indicated on a display panel such as an LCD panel.
In digital cameras, the amount of processing data tends to increase with an increase in pixel density, and accordingly, consideration must be given to the time necessary for image processing. For instance, in the case where a rotatable specific-effect optical element such as a polarizing filter is incorporated in a digital camera, a heavy load is put on a processing circuit provided therein if a display image update process is consecutively performed at all times while keeping up with the rotation of the rotatable specific-effect optical element. Depending on the situation, time delays in image processing may cause a time lag to occur between the image displayed on a display panel, which is viewed by the photographer, and the rotational position of the rotatable specific-effect optical element, or may slow down the photographing response at a time of exposure. In additions under circumstances where the object image indicated on a display panel consecutively changes, it is difficult for even the photographer to have sufficient time to determine an optimum rotational position of the rotatable specific-effect optical element.